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United States Technology

Audio Engineers Built a Shield To Deflect Police Sound Cannons (vice.com) 257

An anonymous reader quotes a report from Motherboard: Over the past two weeks, cops have been deploying every tool at their disposal to suppress worldwide protests and riots over the deaths of George Floyd, Breonna Taylor, Tony McDade, and other Black citizens killed by police. Since the protests began, demonstrators in multiple cities have reported spotting LRADs, or Long-Range Acoustic Devices, sonic weapons that blast sound waves at crowds over large distances and can cause permanent hearing loss. In response, two audio engineers from New York City have designed and built a shield which they say can block and even partially reflect these harmful sonic blasts back at the police. The shield's designers, Dave Rife and Gabe Liberti, were inspired to build the device after marching in the protests in New York City and hearing about LRAD sightings at demonstrations across the U.S.

"It's definitely been on our mind a lot how we've been seeing police instigating violence, and we've heard rumblings here and there about LRADs being spotted in NYC," said Rife, the shield's co-designer, who has previously worked in the architecture industry as an expert in acoustics. "We met on Sunday with the aim of building something that resembles a protest sign but can block a fair amount of sound energy. The idea is there could be a few of these in a car, driven to the location where someone has seen an LRAD, and then carried by hand from there." Rife and Liberti designed their shield to reflect audible sound waves that are condensed and carried via ultrasonic frequencies, and have tested it against a smaller and less powerful version of the LRAD that they built in their studio. It's made from a pine batten structure filled with recycled denim insulation, and covered by a half inch of clear acrylic on both sides, enabling the user to see ahead through a small window. According to a detailed teardown of the LRAD 300X posted by another audio technician, the LRADs produced by Genasys, the company that pioneered the devices, do not use an ultrasonic beam to project sound. However, Rife and Liberti say their design would still be effective against these hyper-directional blasts.

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Audio Engineers Built a Shield To Deflect Police Sound Cannons

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  • by George_Ou ( 849225 ) on Tuesday June 09, 2020 @08:16PM (#60166322)
    They have not tested this against an actual LRAD and it may not even work as well as sub gram NRR 33 Disposable Ear Plugs that can attenuate the signal 33 dB. The LRAD emits higher frequencies which are easily blocked standard Ear Plugs. One person can bring a box of 1000 and pass them out to the crowd and that box would weigh nothing compared to a 50 lb shield.
    • There's always some smart cunt like George. Freedom Fighters build a Freedom Shield only for some smarmy, smug, cynical malcontent like George to come along and point out the impracticalities of the situation. Good one George.
    • Yep, earplugs seem like a more practical and effective solution all around. Maybe wear earplugs and shooting headphones over them.

      What I really worry about is the idea that someone somewhere is going to use a laser weapon at one of these events and blind a crowd full of people. If you did it in a sports stadium you could potentially blind 50,000 people.

    • by AmiMoJo ( 196126 )

      If the cops see these deployed they might thing twice about risking their own hearing though. Just the deterrent factor is valuable.

      33dB might not be enough anyway, the marketing material claims these things can emit 136db and anything over 80db is into hearing damage territory, so probably best to use both.

    • by aitikin ( 909209 )
      The other thing that isn't reported in the summery and I didn't notice in my skimming of the article is that devices like LRAD are reported to cause extra-aural [wikipedia.org] issues for which earplugs will have no prophylactic effect.
  • by jenningsthecat ( 1525947 ) on Tuesday June 09, 2020 @08:58PM (#60166438)

    is a large, light-weight, shallow parabolic reflector that could return enough acoustic energy to the cops to at least make them uncomfortable.

  • by Spaizatski ( 6946336 ) on Tuesday June 09, 2020 @09:29PM (#60166508)
    https://www.youtube.com/watch?... [youtube.com] Somehow the creator of this was legally threatened (details weren't specified) and told to remove the video, adding to the air of mystery. There are several comments posted there by one "Kristal McKinstry" who claims to be one of the co-inventors of the technology underlying the LRAD. Her comments are interesting.
  • Literally anything rigid, flat, and reasonably immovable by air aka massive. You ever point a speaker at a concrete wall? If I had to quickly put something together, I'd say a plate of aluminum or PVC. That'd deflect high pitched sound like a mirror!
    • by jbengt ( 874751 )
      A flat mass like a concrete wall will reflect sound well, as you've said. But a PVC plate will mostly just vibrate with the soundwaves and pass them through, except maybe the highest frequencies, which may be partially reflected. (depends on size and rigidity, in addition to mass)
  • by thegarbz ( 1787294 ) on Wednesday June 10, 2020 @03:10AM (#60166944)

    No they haven't. It seems the only place police are suppressing protests are in the USA. The rest of the world seems to be protesting without issue and police presence there does little more than keep the peace. But then the rest of the world doesn't have a constitutional right to assembly protecting us ... wait that makes no sense.

    Land of the free my arse.

    • I didn't see them burning down businesses in Europe. What I did see was a lot of head-scratching about why people thousands of miles away are protesting about American domestic issues, and the sad answer was that the Americanization of Europe has gotten into too many people's heads, and they simply can't understand that they're not Americans themselves. It doesn't matter to them. They have consumed so much American media that deep down they think live in America. When you've got potential COVID-19 supersp [thelocal.no]

      • Re: (Score:2, Interesting)

        by Anonymous Coward

        I think the headscratching is because a lot of us white Europeans are so utterly privileged we can't even comprehend the scale of it, nor the harm it's done to all the others we've lauded over for centuries.

        We have all the same race issues the Americans do - except our police have a far, far better record of acting impartially and fairly when faced with a mass protest. I wouldn't go as far as to say our police aren't racist, but even there, they have a better record than the US.

        Hence, thousands and thousand

    • by rho ( 6063 )

      constitutional right to assembly

      The full clause is or the right of the people peaceably to assemble, and to petition the government for a redress of grievances

  • It always baffles me when people attack government means of less then lethal options such sonic, water cannons, tear gas, mace, rubber bullets, tasers and so on. These have been under system attack by radicals for decades who want to remove these as options. It is as if people think that if they were to somehow get rid of all the less then lethal options that governments would somehow no longer have the ability to forcibly disperse them.

    It does not matter what the technology is, all less then lethal technol

    • You're suggesting that you are baffled by things so surely the problem must be with those things. If you have cops who have a very low threshold for pulling guns and for firing guns and you give them tasers, they will feel free do use them for everything they can imagine. Cops need to start with some elementary education which cops in other countries get: they are not in Iraq. They should respect the citizens and not treat them as the enemy. They should not disperse crowds when there are demonstrations. The

      • Even in Iraq the presumption that a civilian is the enemy and deserving of being treated as such is wrong, both morally and according to the UCMJ.

  • They are taking non-lethal, non-violent, non-contact crowd control tools from the police forcing the police to rely on tear gas, rubber bullets, batons, and eventually guns and live rounds.
    • by jbengt ( 874751 )

      They are taking non-lethal, non-violent, non-contact crowd control tools from the police . . .

      Where'd you get that? And who is this "They" you are talking about.

  • ... they should go back to firehoses and rubber bullets? Is that better?

    See, if you 'defeat' (and TBH this sounds like something that might work in a lab only) various non-lethal means that the the police have to control riots, it's not like the authorities are going to shrug and say "well I guess we can't control them, we should just go home and let them burn the neighborhood!".

    No, it's going to be back to truncheons, rubber bullets, and CS. And then more serious methods.

    It's a dilemma: non lethal method

    • by swilver ( 617741 )

      I'll accept a solution that doesn't do permanent damage. Water cannons are the only one on that list. The police has no business using lethal force in any situation, leave that to the military. At most they should be able to use force to incapacitate people temporarily.

      Exceptions I suppose for backwater countries where an arms race is allowed between the populace and the police forces.

  • I wouldn't go roleplaying in the street. This isn't harry potter.

  • Comment removed based on user account deletion

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